1. Field of the Invention
The present invention relates to a radiation image reproducing apparatus and, more particularly, to a radiation image reproducing apparatus of the type which senses a radiation image of an object stored in a stimulable phosphor sheet or like recording medium to record it on another recording medium.
2. Description of the Prior Art
A radiation photographing system has been proposed which uses a stimulable phosphor sheet as a recording medium, as disclosed in U.S. Pat. No. 3,859,527 for example. The recording medium is exposed to a radiation transmitted through an object to store a radiation image thereof. Afterwards, the recording medium is stimulated by stimulating rays so that the radiation image may be read photoelectrically to be recorded on another recording medium as a visible image of the object.
In an image reproducing apparatus applicable to the system described above, it is a usual practice to subject radiation image data read out to various image processings such as a gradation processing and a spatial frequency processing and, then, to record the processed data on a photo film or like recording medium as a hard copy, or to reproduce it as a visible image on a cathode-ray tube (CRT) or any other suitable display device.
When a stimulable phosphor sheet is exposed to an imagewise radiation of an object, information on the object and exposure is entered into the image reproducing apparatus to be stored in a file. Some of the information is read out of file in the event of the subsequent reproduction of the object's image to be recorded as visible information on a hard copy of the reproduced image. The visible object and exposure information may be utilized for diagnoses by a doctor, for example. Such information may be typified by identification (ID) data on a patient or like object and exposure conditions which include exposed object's part and exposing method.
To facilitate a diagnosis, a patient's specific part is often exposed to radiations in various angles or directions as may be the case with the thorax. Supposing a case wherein the thorax of a human body was photographed from the rear thereof, a doctor or like specialist will customarily make a diagnosis turning over the radiation image to observe it from the front.
The image output from the radiation image reproducing apparatus stated above is generally recorded by a laser beam or the like on a photosensitive film sheet which is coated with a layer of photosensitive emulsion on one surface thereof. In this connection, difficulty heretofore experienced is that concerning an exposure from the rear of a patient, turning over such a film causes the other non-coated surface to face the person to often make the observation of the image uneasy, because the coated surface tends to reflect external light. Furthermore, it will be hard to read the object and exposure data recorded on the film when they are turned over together with the image.
The image processings already mentioned are performed within a processing system based on the input data related with an object and an exposure. In analyzing a reproduced image on a hard copy produced from the processing system, it is often required to know what kind of image processings the reproduced image underwent. Data on image processings will be readily attained if a diagnosis is made every time a hard copy is output from the processing system. However, in a totalized processing system which concentratively processes numerous stimulable phosphor sheets to produce numerous hard copies, it will be difficult in practice to properly match the data to the individual hard copies.